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Three diverse career paths in physics

The project leader

By Stephen Battersby

Lyn Evans, project leader for the Large Hadron Collider at CERN, Geneva

Lyn Evans is building the biggest machine in the world. The Large Hadron Collider, a 27-kilometre-long chain of superconducting magnets at CERN in Geneva, Switzerland, will be the most powerful particle accelerator ever built. By smashing together particles and reading the debris, it should take physicists to a new level in our understanding of nature. Managing such a vast project is no simple task. “It’s a huge mixture of physics, engineering, politics… and contract litigation,” he says.

Evans has been building particle accelerators for more than 30 years. He arrived at CERN in 1969 on a three-month contract to work on a linear accelerator. Two years later, the Super Proton Synchrotron (SPS) was approved to compete with Fermilab’s proton accelerator in the US. Its aim was to see what might exist at higher energies, and whether the complex set of heavy particles discovered in earlier accelerators had some underlying symmetry. It was Evans’s job to design the hardware to keep the SPS’s highly unstable beams of protons tightly focused as they were accelerated.

In the late 1970s, Evans turned down a job that many other scientists would have jumped at – working on the Joint European Torus, a prototype nuclear fusion reactor in Oxfordshire. “It was an exciting time at CERN,” he explains. One thing he was working on was how to accelerate antiprotons to collide head-on with protons in the SPS, generating enough energy to create W and Z bosons. The work paid off, and in 1983 the discovery of these fundamental particles confirmed physicists’ theories of how electromagnetism is linked to the weak nuclear force.

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In 1990, Evans was appointed department head of the SPS, and eventually ran the Large Electron Positron Collider, which occupied the tunnel now taken up by the LHC. “It was difficult at the beginning, handling so many people – not an easy transition from being an innocent scientist with very little knowledge outside accelerator science. I don’t know how you train for it. You just learn on the job and become streetwise,” Evans recalls.

His appointment at the LHC in 1993 added a political dimension to Evans’s career. “The early 1990s was a bumpy period.” A lack of funding from CERN’s member states meant that, as well as designing the machine, he had to go on the road along with CERN head Christopher Llewellyn Smith to persuade non-members to chip in – and the US, Japan, Russia, India and Canada did so.

The collider is now built, but a lot more work will be needed before it is up and running. Evans and his team are now cooling down the first eighth of the LHC. “That alone is 1.5 times bigger than anything that’s been done before,” says Evans. The accelerator’s electromagnets have to be very cold to superconduct, at which point they are powerful enough to accelerate the beams to the necessary high energy. The final stage in the cooling process involves feeding in liquid helium at a temperature of 1.9 kelvin, which is so cold that the helium becomes superfluid. “It’s a quantum liquid, with very unusual properties as an engineering material. It will flow through the tiniest crack, which makes life challenging for the welders,” he says. “In the lab, we normally play with this stuff in gram quantities; here, we’ve got 100 tonnes.”

By the end of this year, Evans hopes to finally get beams of protons circulating around the machine, then 2008 will be “the big year”, taking the LHC up to full energy. At this point, his machine might begin to find evidence for heavy “superpartners” of ordinary matter, or extra dimensions of space, or just possibly start to manufacture microscopic black holes.

The academic

Peter Coles, professor of cosmology, University of Nottingham

“There’s a curious thing going on in cosmology,” says Peter Coles. “For the first time there is a standard model that fits the data, but it’s weird&colon; 70 per cent of the universe is dark energy and we have no idea what it is, and 25 per cent is dark matter and we don’t know what that is. If somebody had asked me how to design a universe, frankly I wouldn’t have come up with that. It seems quite unnatural from the physics point of view, which suggests to me that at some level it might be wrong.”

If I was asked to design a universe, I wouldn’t have chosen that

That is an exciting prospect for Coles, the first professor of cosmology appointed at the University of Nottingham. The main aim of his research is to explain the pattern of matter in the universe, calculating how galaxies and clusters might have evolved.

Coles was not always interested in cosmology. His undergraduate degree in natural sciences at the University of Cambridge did include one cosmology course, but it was mostly about observations, and he had already decided to be a theorist. “It didn’t set me aflame,” he admits. When he was interviewed for a PhD place at the University of Sussex, his soon-to-be-supervisor John Barrow suggested a project working on the cosmic microwave background (CMB) – the radiation emitted by the universe when it was only 380,000 years old. Specifically, the aim was to investigate what it might look like. “What seemed interesting to me was not to do with cosmology, but the fact that it involved statistics and mathematical probabilities,” says Coles. “That’s when I started getting into cosmology. Until you start working in a field you don’t realise what’s involved.”

Since then he has used the same kind of computerised statistical analysis that finds subtle patterns in a mass of data to look at the large-scale structure of the universe&colon; the pattern of galaxies, galaxy clusters and superclusters, which grew out of those ancient fluctuations. Finding the time for research can be difficult, however, says Coles, because of the competing demands of academic life. “It’s about 50 per cent teaching and 50 per cent admin. The rest of the time is for research,” he jokes. “Having said that, the advantage of the academic life is that you’re basically doing as a job what you’d be doing as a hobby even if you weren’t being paid for it.”

Recently, Coles has gone back to studying the cosmic microwave background. “Lots of features are not well understood,” he says. Although NASA’s microwave probe WMAP largely confirmed the standard model of cosmology in 2003, it also spotted features that don’t fit, such as the “axis of evil” – an unexpected alignment of temperature patterns in the CMB.

That could be good news for those entering the field today. “The edifice we’ve assembled has sufficient cracks in it that it might all come tumbling down, which is the most exciting thing that can happen in science.”

The entrepreneur

Hugh Cormican, managing director of Andor Technology, Belfast

Some physicists do not dream of academic achievement. “I went into physics with the idea I wanted to be in business,” says Hugh Cormican. “I anticipated that after my PhD I would work for a big multinational, get some experience, and then set up on my own.”

However, an opportunity presented itself much sooner, while Cormican was still studying for his PhD at Queen’s University, Belfast, in the late 1980s. As a tool for their laser research, he and colleague Donal Denvir used their physics know-how to build a highly sensitive digital camera. They set up Andor Technology to develop it into a commercial product for use in scientific research. “It knocked my PhD project back a wee while,” he admits.

Andor is now worth £30 million, and has about 150 staff around the world. Scientists use the company’s cameras for photographing everything from faint galaxies to living tissue. For example, one is used to record how proteins work. Biologists add fluorescent chemicals to a sample of tissue, and illuminate them with laser light. Strapped to a microscope, the camera picks up changes in the fluorescence, which can reveal how a protein binds itself to a surface, for instance. A highly sensitive camera is vital because if the illumination is too strong you’ll disturb the cell or even kill it.

Cormican manages to balance an understanding of this technical side of Andor with business acumen. “I like to spend time in the lab with my sleeves rolled up, but I also like to get out and meet people. It’s not a chore. I still think it’s one of the best jobs in the world.

“I do think that physics is a fundamentally good subject for entrepreneurs. Business is something physicists tackle with similar zeal to tackling other problems&colon; you build a model and test it; if it works you go further, otherwise you change the model,” he says.

Nor does Cormican think the stereotypical introversion of physicists is a serious barrier to business success. “Physicists have this reputation for geekiness, but things have moved on – the geeks mostly run the world now.”